Bottom Line:
However, after adjusting confounding factors, the higher CS rate was significantly associated with advanced maternal age, higher BMI, lower Bishop scores and iparity, with no demonstrable tie to labor induction.Neonatal outcome in the two groups were comparable.Although CS rate was higher in women whose labor was induced than those who had spontaneous labor, this higher rate was associated with maternal age, BMI, Bishop scores and parity, but was not impacted by labor induction per se.

Affiliation: Department of Obstetrics and Gynecology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.

ABSTRACT

Objective: To investigate whether the cesarean section (CS) rate is increased in women whose labor was induced compared to those who had spontaneous labor at term pregnancy.

Methods: A retrospective study was performed in women whose labor was either induced (induction group, n=497) or spontaneous (spontaneous group, n=878) at 37+0 to 41+6 weeks of gestation from January 2008 to June 2009. Maternal age, parity, body mass index (BMI), Bishop scores, gestational age, hypertension, diabetes, delivery mode, indications for CS, neonatal outcome were compared between the two groups. Multiple logistic regression analysis was used to examine the association between the CS rate and labor induction after adjusting for potential confounding variables.

Results: CS (17.3% vs. 5.3%, P<0.001) and vacuum-assisted delivery (10.7% vs. 6.4%, P<0.001) rates were significantly higher in the induction group compared to the spontaneous group. The CS rate in the induction group was higher than the spontaneous group not only in iparous women (25.3% vs. 8.6%, P<0.001), but also in multiparous women (3.8% vs. 0.3%, P=0.002). However, after adjusting confounding factors, the higher CS rate was significantly associated with advanced maternal age, higher BMI, lower Bishop scores and iparity, with no demonstrable tie to labor induction. Neonatal outcome in the two groups were comparable.

Conclusion: Although CS rate was higher in women whose labor was induced than those who had spontaneous labor, this higher rate was associated with maternal age, BMI, Bishop scores and parity, but was not impacted by labor induction per se.

Mentions:
During the study period, 2,500 women had term deliveries at our institute. A total of 1,125 were excluded using exclusion criteria. Labor was induced in 497 women, and 878 women had spontaneous labors (Table 1). The most common indication for labor induction was the past the due date (Fig. 1A). The indications of labor induction were different for iparous and multiparous women (Fig. 1B, C). CS rate by indication for labor induction was variable (Fig. 2); highest for hypertension (27%), followed by large-for gestational age (24.3%) and diabetes (24.0%). CS rate by gestational age showed a "J-shaped" curve (Fig. 3); 15.7% in 37 weeks, lowest in 38 (5.8%) and 39 (6.2%) weeks, and a steadily increasing rate after 40 weeks of gestation (10.4% and 18.8%, at 40 and 41 weeks of gestation). However, higher CS rates in iparous women (vs. multiparous women) and in the induction group (vs. spontaneous group) were observed in all gestational weeks (Fig. 3).

Mentions:
During the study period, 2,500 women had term deliveries at our institute. A total of 1,125 were excluded using exclusion criteria. Labor was induced in 497 women, and 878 women had spontaneous labors (Table 1). The most common indication for labor induction was the past the due date (Fig. 1A). The indications of labor induction were different for iparous and multiparous women (Fig. 1B, C). CS rate by indication for labor induction was variable (Fig. 2); highest for hypertension (27%), followed by large-for gestational age (24.3%) and diabetes (24.0%). CS rate by gestational age showed a "J-shaped" curve (Fig. 3); 15.7% in 37 weeks, lowest in 38 (5.8%) and 39 (6.2%) weeks, and a steadily increasing rate after 40 weeks of gestation (10.4% and 18.8%, at 40 and 41 weeks of gestation). However, higher CS rates in iparous women (vs. multiparous women) and in the induction group (vs. spontaneous group) were observed in all gestational weeks (Fig. 3).

Bottom Line:
However, after adjusting confounding factors, the higher CS rate was significantly associated with advanced maternal age, higher BMI, lower Bishop scores and iparity, with no demonstrable tie to labor induction.Neonatal outcome in the two groups were comparable.Although CS rate was higher in women whose labor was induced than those who had spontaneous labor, this higher rate was associated with maternal age, BMI, Bishop scores and parity, but was not impacted by labor induction per se.

Affiliation:
Department of Obstetrics and Gynecology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.

ABSTRACT

Objective: To investigate whether the cesarean section (CS) rate is increased in women whose labor was induced compared to those who had spontaneous labor at term pregnancy.

Methods: A retrospective study was performed in women whose labor was either induced (induction group, n=497) or spontaneous (spontaneous group, n=878) at 37+0 to 41+6 weeks of gestation from January 2008 to June 2009. Maternal age, parity, body mass index (BMI), Bishop scores, gestational age, hypertension, diabetes, delivery mode, indications for CS, neonatal outcome were compared between the two groups. Multiple logistic regression analysis was used to examine the association between the CS rate and labor induction after adjusting for potential confounding variables.

Results: CS (17.3% vs. 5.3%, P<0.001) and vacuum-assisted delivery (10.7% vs. 6.4%, P<0.001) rates were significantly higher in the induction group compared to the spontaneous group. The CS rate in the induction group was higher than the spontaneous group not only in iparous women (25.3% vs. 8.6%, P<0.001), but also in multiparous women (3.8% vs. 0.3%, P=0.002). However, after adjusting confounding factors, the higher CS rate was significantly associated with advanced maternal age, higher BMI, lower Bishop scores and iparity, with no demonstrable tie to labor induction. Neonatal outcome in the two groups were comparable.

Conclusion: Although CS rate was higher in women whose labor was induced than those who had spontaneous labor, this higher rate was associated with maternal age, BMI, Bishop scores and parity, but was not impacted by labor induction per se.